athena: Add the concept of Activity and related managers.

athena/task/public/task.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ATHENA_TASK_TASK_H_
+#define ATHENA_TASK_TASK_H_
+
+#include <string>
+
+#include "athena/athena_export.h"
+
+typedef unsigned int SkColor;
+
+namespace aura {
+class Window;
+}
+
+namespace athena {
+

[Mr4D (OOO till 08-26), 2014/05/27 20:12:42]

Could you please add a comment towards what a Task actually is?

+class ATHENA_EXPORT Task {
+ public:
+  virtual ~Task() {}
+
+  // Returns a color most representative of this task.
+  virtual SkColor GetRepresentativeColor() = 0;
+
+  // Returns a title for the task.
+  virtual std::string GetTitle() = 0;
+
+  // Returns the native window containing the task.
+  virtual aura::Window* GetNativeWindow() = 0;

[Mr4D (OOO till 08-26), 2014/05/27 20:12:42]

I might be blended by the name "Task" and "TaskManager" here. Is this supposed
to be an high level accessor for a V1/V2/NaCl app / browser object?

If so - we should add here some calls to unify their resource handling - like a
query mechanism about how much of what is used and / or setting the state of
such a task. (I can elaborate more on this if this is what it is).

If I am wrong and this is meant to be an "UI representation"
of a user's task - like: send an email - (and it has nothing to do with an OS
task) could we use a term like "Activity" instead of "Task"?

[sadrul, 2014/05/27 20:30:45]

Something like that. This is essentially supposed to be the UI representation of
a V1/V2/NaCl app / browser object. Perhaps 'TaskUI' explains it better. See the
implementation of WebTask, for example, which provides the UI for athena for a
content::WebContents.

+};
+
+}  // namespace athena
+
+#endif  // ATHENA_TASK_TASK_H_